Gould

Prospect, Undetermined

Commodities and mineralogy

Main commodities Ag; Cu; Pb; Zn
Ore minerals chalcopyrite; galena; malachite; pyrite; sphalerite
Gangue minerals albite; epidote; garnet; quartz; wollastonite

Geographic location

Quadrangle map, 1:250,000-scale CR
Quadrangle map, 1:63,360-scale B-2
Latitude 55.27707
Longitude -132.61723
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Gould prospect is near the southwest tip of Gould Island, about 0.4 mile north-northwest of the southeast corner of section 15, T. 76 S., R. 84 E.

Geologic setting

Geologic description

The rocks in the vicinity of the Gould prospect are mainly marble of the Wales Group of Cambrian or older age, and skarn composed of albite, epidote, garnet and wollastonite (Eberlein and others, 1983; Brew, 1996). A large body of Cretaceous, epidotized gabbro and diorite, which makes up most of Gould Island, is just east of the prospect (Wright and Wright, 1915; Herreid and others, 1978; Maas and others, 1991). There are two types of deposits: 1) chalcopyrite, galena, and sphalerite occur in veinlets in hornfels, and 2) a 4-foot quartz vein contains abundant chalcopyrite, with pyrite and malachite. The prospect has been sampled several times in recent years. A sample of the vein collected by Herreid and others (1978) contained 3.0 ounces of silver per ton, 0.91 percent copper, 140 parts per million (ppm) lead, and 0.21 percent zinc. Several samples of dump material collected by Maas and others (1991) contained up to 3.7 ppm silver, 1.4 percent copper, and 1.8 percent zinc. A chip sample across the quartz vein contained 802 parts per billion gold, 6.7 ppm silver, 1.74 percent copper, and 1.39 percent zinc. Several high-grade samples collected by Hedderly-Smith (1999 [Inventory]) contained 2,156 ppm copper, 2.3 percent lead, more than 10 percent zinc, and 19.9 ppm silver. All of the workings probably date to before World War I; they include a 70-foot adit, a 10-foot shaft, and several trenches and prospect pits.
Geologic map unit (-132.618886316331, 55.2767180486288)
Mineral deposit model Ag-Pb-Zn skarn and polymetallic vein (Cox and Singer, 1986; models 18c and 22c).
Mineral deposit model number 18c, 22c
Age of mineralization Probably related to a nearby Cretaceous intrusion.
Alteration of deposit Marble is altered to albite-epidote-garnet-wollastonite skarn.

Production and reserves

Workings or exploration All of the workings probably date to before World War I; they include a 70-foot adit, a 10-foot shaft, and several trenches and prospect pits.
Indication of production None

Additional comments

The Gould prospect is on or surrounded by land that has been conveyed to the Sealaska Corporation, who hold the surface and subsurface rights, or the land is under application for transfer to them.

References

MRDS Number A010052

References

Glavinovich, P.S., 1987, Sealaska Corporation Minerals Breifing Book, December 1987: Sealaska Corporation, 40 p. and plates. (Unpublished report held by Sealaska Corporation, Juneau, Alaska).
Hedderly-Smith, D.A., 1991, Report of the 1990 field season-Sealaska Mineral Reconnaissance Project: Sealaska Corporation: Sealaska Corporation, 2 vols., 180 p., 13 plates. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1992, Report of the 1991 field season - Sealaska Mineral Reconnaissance Project: Sealaska Corporation, 2 vols., 225 p. 23 plates. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1997, Report of the 1996 work in the Mount Jumbo area-Sealaska minerals reconnaissance project: Sealaska Corporation, 51 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1999, Inventory of metallic mineral prospects, showings and anomalies on Sealaska lands, 1988 through 1998: Sealaska Corporation, Juneau, Alaska, 217 p. (internal report held by Sealaska Corporation, Juneau, Alaska).
Reporters D.J. Grybeck (Applied Geology)
Last report date 5/1/2004